The invention relates to a porous electrode comprising at least a porous catalytic layer containing a catalytically active noble-metal of the type described below, carbon and a polymeric binder and a porous metallic collector is situated on the electrolyte-side of this layer. An electrode of this kind is known from the Netherlands patent application No. 7214900 laid open for public inspection.
Electrodes of this kind are particularly suitable in fuel cells. During operations the fuel used penetrates into the pores of the catalytic layer, where it is burnt galvanically. The generation of electric current takes place throughout the catalytic layer and the current generated is collected by a collector system and transmitted. The electrode is in contact with a suitable electrolyte which closes the circuit within the fuel cell and by which the products of reactions occurring at the cathode and anode can also be discharged.
A drawback of the known electrode is the comparatively large amount of noble-metal that is required for its manufacture. For instance, the known electrode contains 0.4 mg/cm.sup.2 of platinum and palladium, which excludes large-scale application of the electrode in view of the present short supply of noble-metals. The problems about the fuel cell containing noble-metals have been discussed, e.g., in the Report "Elektrochamische Aspekten van de Energievoorziening" by the Stichting Nederlands Instituut voor Elektrowarmte en Elektrochemie NIVEE, 1975, pp. 62 and 63. According to this article reduction of the amount of noble-metal in the electrode might be considered, but this will lead to a lower efficiency and a lower power density, while also the rise in production cost is considered to be a problem.
The invention meets the need of such an electrode with a much lower noble-metal content, while the excellent characteristics as regards efficiency, power density and simplicity of manufacture are retained.